The present invention relates to a pressurized fluid delivery system including a high pressure fluid reciprocating pump and fluid flow control devices in a fluid cylinder block to control the fluid inlets and outlets from the cylinder block. Reciprocating pumps are typically used in high pressure fluid delivery systems to create a high pressure fluid jet such as water to be used for cleaning, for example. Reciprocating pumps of this type generally include a plurality of plungers and cylinders and develop pressures in excess of 10,000 psi thereby subjecting their parts to significant stresses and fatigue failure due to stress fluctuations. Accordingly, because of the severe service environment of high pressure pumps of this type, maintenance may be frequently required particularly to the fluid cylinder block forming the pressure end of the pump. Such systems, as disclosed in commonly assigned U.S. Pat. No. 4,432,386, tend to minimize stress concentration points along with ease of maintenance and durability of construction and are all exceedingly important in determining the overall service performance of high pressure pumps. With all such high pressure pumps, a considerable amount of input energy is required and it is therefore highly desirable to also increase the efficiency of the pump as well as its ease of maintenance. In addition, the single fluid cylinder blocks of the present invention are formed of stainless steel and are very expensive. If a mistake occurs during machining, the entire block must be discarded. In addition, the prior art valve members have vanes extending radially therefrom and therefore have substantial friction because of the large contact area with the fluid cylinder block. Further, these devices must be used at high pressures because of the suction feed pressure required to open and close the valves. Thus, they are not able to be used with low pressure fluid systems.
The present invention overcomes the disadvantages of the prior art by providing a pressurized fluid delivery system in which the pump plungers each have an individual fluid cylinder block attached thereto. Thus, there are three or more smaller pieces necessary for the system to function rather than one large fluid cylinder block. In the construction of these fluid cylinder blocks, if an error is made, only the small block on which the error is made is discarded. Further, because there are three or more individual fluid cylinder blocks instead of one large one, they are sufficiently light that one person can lift each one.
In addition, a fluid flow control valve is placed in the inlet orifice of each of the fluid cylinder blocks and a control valve assembly is placed in the outlet orifice of each fluid cylinder block. These novel control valves are formed such that they have less restriction to fluid flow than in the conventional configurations, have less friction with the guide in which they operate and require less suction feed pressure than is normally required. Each valve has a valve body having at least one fluid path extending therethrough and having a fluid outlet orifice and at least one fluid inlet orifice. A valve member has a piston on one end for blocking the fluid outlet orifice in a first position and opening the fluid outlet orifice in a second position. A stem forms the other end of the valve member and is slidably mounted in an orifice in the valve body with the stem extending beyond the valve body on the inlet side. A shoulder is formed on the outer end of the valve stem and a seat is formed in the valve body inlet side opposite the shoulder. A biasing device such as a spring is mounted between the stem shoulder and the valve body seat to resiliently urge the valve member piston in the first position to block the fluid outlet orifice and prevent the fluid flow through the valve body.
The fluid flow control device is used in a pressurized fluid delivery system wherein a plunger assembly has at least one reciprocating plunger with a power unit for driving the plunger with reciprocating motion. A fluid cylinder block is provided for each reciprocating plunger and individually associated therewith in fluid-tight relationship. The fluid cylinder block has a cavity for receiving one of the plungers so as to create a suction when the plunger moves in one direction and to create a pressure when the plunger moves in the other direction. A fluid inlet manifold and a fluid outlet manifold are individually and operatively coupled to the cavity in each fluid cylinder block to admit fluid to and receive fluid from the cavity in response to the reciprocating motion of the plunger. A first fluid control valve is placed in the fluid inlet manifold to allow fluid into the cavity only when the plunger creates suction. A second fluid control valve in the fluid outlet manifold allows fluid to escape from the cavity only when the plunger creates a pressure in the cavity.
Thus, it is an aspect of the present invention to provide an improved fluid flow control device for use in a fluid control structure.
It is another aspect of the invention to provide a valve body for use with a valve member including a piston and a stem in a fluid flow control device.
Finally, it is an important aspect of the present invention to provide a pressurized fluid delivery system that includes a fluid flow control device to admit the fluid to and receive the fluid from the cavity in response to reciprocating motion of a plunger.